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Analysis of the causes and solutions of Glass Fiber exposure

Nov. 15. 2019

In order to improve the strength and temperature resistance of the product, the use of glass fiber to enhance the modification of GF Reinforced PP has become a very good choice. A large number of facts also prove the good performance brought by glass fiber. However, glass fiber and plastic itself are two different materials, which naturally leads to compatibility problems between the two.

Glass fiber exposure is a direct manifestation of the compatibility problem. The glass fiber exposure is also a problem that often encounters and plagues many friends during the injection molding process of glass fiber materials.

So how does the glass fiber exposure come from? In short, from the shape of the glass fiber, the glass fiber has a long glass fiber and a short glass fiber. It is a bundle and is white. Adding fiber is a blend of glass fiber and resin.

When the glue is applied, the flow of the material is similar to the flow of the liquid. Everyone should have seen the river. When there are some branches and other debris in the river, there are often some such rivers along the coast. If in the injection molding, the glass fiber is exposed.

This is because the flow of glass fiber is much worse than that of plastic. The flow of plastic in the mold flows forward from the middle of the interlayer. The two sides flow outwards, so the best fluidity is to run the most. In front, the poor fluidity will stay on the surface of the mold.

At the same time, glass fiber has the function of promoting crystallization, and PP and PA are all crystalline materials. Crystallization is quick to cool; if it cools quickly, the glass fiber is difficult to be bound and covered by the resin, so it is easy to produce glass fiber.

Glass Fiber PP Granules

Glass Fiber PP Granules

As a Glass Fiber PP Granules Wholesale, the current common solutions are as follows:

First, the material aspect:

1. Considering the compatibility of glass fiber and matrix, surface treatment of glass fiber, such as adding some coupling agent and graft;

2, the addition of lubricants, lubricants mainly take into account the dispersion of glass fiber and some lubricants have external lubrication, easy to run to the surface of the product to form a smooth layer.

3, there are other fillers have improved effects, here are not listed one by one.

Second, injection molding processing:

1. Increase the material temperature and mold temperature;

2, high pressure and high speed;

3. Use RHCM.

Because of the molten plastic cures too quickly when it contacts the mold wall, the glass fiber cannot be completely covered, that is, the glass fiber the phenomenon occurs on the surface. For RHCM molding, due to the high mold temperature, the glass fiber at the cavity interface can be completely covered by the plastic melt, and since the portion is in a molten state, the orientation of the glass fiber tends to be uniform, thereby ensuring uniformity of shrinkage, thereby ensuring The molding quality.

Third, the mold aspect

Deliberately make the appearance of the product into a matte or etched surface to reduce the visual response of the glass fiber.

At present, the most used fiber-added materials on the market are nylon fiber-reinforced materials. Due to the exposure of glass fiber, the application of such products has been limited, and it is mainly applied to some high-strength structural parts. Anything that uses glass fiber material as the appearance part is basically a matte surface or an etched surface (such as a power tool), because it is difficult to achieve a beautiful appearance with ordinary glass fiber.

We also have High Gloss PP Granules on sale, welcome to come and consult.